Communication device and communication method as well as communication system

ABSTRACT

A terminal intermittently operates while receiving paging information and other necessary information from a base station. In the terminal cycles of DRX with different lengths are combined in a hierarchy manner to determine an intermittent operation period. Upper DRX in the hierarchy has a longer cycle than lower DRX. A period using a cycle of the immediately lower DRX is determined based on information on the cycle of the upper DRX. An intermittent operation of a communication processing unit is controlled based on information on the cycle of DRX in a period using information on a cycle of the lowermost DRX.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 13/702,601, filed Dec. 7, 2012, which is a NationalStage of PCT/JP11/61003, filed May 12, 2011, and claims the benefit ofpriority from prior Japanese Patent Application JP 2010-145645, filedJun. 25, 2010, the entire content of which is hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to a communication device operating as aterminal in a communication system having a base station accommodatingthe terminal, and a communication method as well as a communicationsystem, and particularly to a communication device for reducing consumedpower due to intermittent reception while receiving paging informationor other necessary information from a base station, and a communicationmethod as well as a communication system.

BACKGROUND ART

A variety of communication services have been spread due to widely-usedinformation processing and information communication techniques, andparticularly communication systems including cell phones have beenremarkably developed. At present, for 3GPP (Third Generation PartnershipProject), the global standard of the third generation (3G) mobilecommunication system “IMT (International MobileTelecommunications)-2000” defined by ITU (InternationalTelecommunication Union) is being standardized. One data communicationspecification “LTE (Long Term Evolution)” defined by 3GPP is a long-termadvanced system directed for the fourth generation (4G) IMT-Advanced,and is called “3.9G (super 3G).”

For example, a communication system having a base station accommodatinga terminal has a problem of how to reduce consumed power of theterminal. In particular, it is important to reduce consumed power whenthe terminal is not making communication. Intermittent reception iswidely known as one method for solving the problem. Intermittentreception is a communication control system for keeping a period forreceiving a signal from a communication network at minimum while theterminal is not making communication, and for powering off a receiverduring the remaining period thereby to reduce consumed power. Forexample, a cell phone powers on the receiver for receiving essentialinformation such as paging information for a communication operationfrom a base station and powers off the receiver during other period. Forthe above 3GPP, an outline of the intermittent reception as DRX(discontinuous reception) is described (see Non-Patent Document 1, forexample).

There are proposed a method for dividing terminals into a plurality ofgroups, shifting a cycle of DRX per group, and reducing a rate of the ONstate in each cycle of DRX thereby reducing consumed power (see PatentDocument 1, for example), and a method for using DRX with differentcycles depending on a time (for example, daytime and nighttime), therebyfurther elongating the cycle of DRX (see Patent Document 2, forexample).

A communication network is widely used in other than terminals directlyused by persons for communication such as meters, automatic venders andelectronic advertisements in addition to normal terminals directly usedby persons such as conventional cell phones and PC (personal computer).In the following, the communication which is not directly used bypersons is called MTC (Machine Type Communication), and a terminal whichis not directly used by a person for communication is called a MTCterminal.

For MTC, a communication frequency necessary for the MTC terminal isrelatively lower than the normal terminals (such as once a day, once aweek or once a month), and the amount of data used for communication ata time is not large. On the other hand, it is expected that remarkablysmall consumed power is needed for the MTC terminal.

When the cycle of DRX is simply made longer for reducing consumed power,the terminal can fail to receive system information or paginginformation transmitted from the communication network. Thus, theterminal intermittently operates while securing a chance to accuratelyreceive information from the communication network (the base station),thereby to further reduce consumed power of the terminal.

It is assumed that the communication of the MTC terminal is madeaccording to a communication schedule desired by users inside thecommunication network or users outside the communication network. Inthis case, the communication network (the base station) needs to graspthe communication schedule and reflect it on the DRX setting in order tomeet the conditions of the user-desired communication schedule.

CITATION LIST Patent Documents

-   Patent Document 1: Japanese Patent No. 2669891-   Patent Document 2: Japanese Patent No. 3270306

Non-Patent Document

-   Non-Patent Document 1: 3GPP TS36.321, “Evolved Universal Terrestrial    Radio Access (E-UTRA) Medium Access Control (MAC) protocol    specification (Release 9)”

i. SUMMARY OF THE INVENTION Problems to be Solved by the Invention

It is an object of the present invention to provide a communicationdevice excellent and capable of intermittently operating as a terminalsuitably in a communication system having a base station accommodatingthe terminal, and a communication method as well as communicationsystem.

It is another object of the present invention to provide a communicationdevice excellent and capable of intermittently operating as a terminalsuitably while receiving paging information or other necessaryinformation from a base station, and a communication method as well as acommunication system.

It is still another object of the present invention to provide acommunication device excellent and capable of suitably makingcommunication as a terminal while intermittently operating according toa communication schedule desired by users inside and outside acommunication network, and a communication method as well as acommunication system.

Solutions to Problems

The present application has been made in view of the above problems, andan invention according to claim 1 is a communication device including: acommunication processing unit for performing digital processing andanalog processing for transmitting and receiving data; and anintermittent operation control unit for determining whether to enter anintermittent operation period for intermittently operating thecommunication processing unit per second cycle by use of information ona first cycle longer than the second cycle, and for intermittentlyoperating the communication processing unit.

With an invention according to claim 2 of the present application, thecommunication device according to claim 1 has a normal operation mode inwhich a communication operation is always performed in the communicationprocessing unit and an intermittent operation mode in which acommunication operation of the communication processing unit isintermittently performed. The intermittent operation control unitdetermines, based on the first cycle, whether to enter the intermittentoperation period in the intermittent operation mode.

With an invention according to claim 3 of the present application, inthe communication device according to claim 1 or 2, the intermittentoperation control unit turns off at least part of circuits in thecommunication processing unit in a period other than the intermittentoperation period.

With an invention according to claim 4 of the present application, theintermittent operation control unit of the communication deviceaccording to claim 1 generates a first timing signal which is switchedon or off by the first cycle and a second timing signal which isswitched on or off by the second cycle based on control information onthe first and second cycles from a predetermined base station when beingaccommodated in a communication network of the base station, anddetermines the intermittent operation period based on the first timingsignal and intermittently operates the communication processing unitbased on the second timing signal in the intermittent operation period.

With an invention according to claim 5 of the present application, inthe communication device according to claim 4, the ON period of thefirst timing signal is longer than the ON period of the second timingsignal.

With an invention according to claim 6 of the present application, theintermittent operation control unit of the communication deviceaccording to claim 4 assumes the ON period of the first timing signal asthe intermittent operation period, turns off at least part of thecircuits in the communication processing unit in the OFF period of thefirst timing signal, turns on a communication operation of thecommunication processing unit in the ON period of the second timingsignal in the intermittent operation period, and turns off thecommunication processing unit in the OFF period of the second timingsignal.

With an invention according to claim 7 of the present application, theintermittent operation control unit of the communication deviceaccording to claim 4 starts the intermittent operation period when thefirst timing signal is turned on in other than the intermittentoperation period, terminates the intermittent operation period when thefirst timing signal is turned on in the intermittent operation period,turns on a communication operation of the communication processing unitin the ON period of the second timing signal in the intermittentoperation period, and turns off at least part of the circuits in thecommunication processing unit in the OFF period of the second timingsignal.

With an invention according to claim 8 of the present application, theintermittent operation control unit of the communication deviceaccording to claim 4 assumes the ON period of the first timing signal asthe intermittent operation period, turns off at least part of thecircuits in the communication processing unit in the OFF period of thefirst timing signal, turns on a communication operation of thecommunication processing unit when the second timing signal is turned onin the OFF state of the communication processing unit in theintermittent operation period, and turns off the communicationprocessing unit when the second timing signal is turned on in the ONstate of the communication operation of the communication processingunit.

With an invention according to claim 9 of the present application, theintermittent operation control unit of the communication deviceaccording to claim 4 turns off at least part of the circuits in thecommunication processing unit when all necessary reception processingfrom the communication network ends even in a period which is determinedto turn on the communication processing unit based on the second timingsignal in the intermittent operation period.

With an invention according to claim 10 of the present application,predetermined correction processing is performed on a receiver in thecommunication processing unit when at least part of the circuits in thecommunication processing unit of the communication device according toclaim 1 enters the intermittent operation period from the OFF state andreceives radio frames again.

With an invention according to claim 11 of the present application, inthe communication device according to claim 10, predetermined correctionprocessing is performed on a receiver in the communication processingunit in the intermittent operation period and when the communicationprocessing unit is in the OFF state.

With an invention according to claim 12 of the present application, thecommunication device according to claim 1 is configured such that thefirst intermittent operation mode has a first-2 cycle shorter than thefirst cycle, and when a predetermined even occurs, the intermittentoperation mode switch unit replaces the first cycle with the first-2cycle and determines a period of entering the second intermittentoperation mode.

An invention according to claim 13 of the present application is acommunication method including: a first step of determining whether toenter an intermittent operation period for intermittently operating acommunication device based on information on a first cycle; and a secondstep of switching an ON state of a communication operation of thecommunication device and an OFF state of at least part of circuits persecond cycle shorter than the first cycle in the intermittent operationperiod.

With an invention according to claim 14 of the present application, inthe invention according to claim 13, the communication device has anormal operation mode of always performing a communication operation andan intermittent operation mode of intermittently performing acommunication operation. The first step of the communication methodaccording to claim 13 determines whether to enter the intermittentoperation period in the intermittent operation mode based on theinformation on the first cycle, and further has a step of turning offthe communication device in other than the intermittent operation periodin the intermittent operation mode.

An invention according to claim 15 of the present application is acommunication method including a first step of notifying parameters ofthe first intermittent operation mode for intermittent operation perfirst cycle and parameters of the second intermittent mode forintermittent operation per second cycle shorter than the first cycle,and a second step of notifying control information on the network to acommunication device in the network in association with the firstintermittent operation mode or the second intermittent operation mode.

An invention according to claim 16 of the present application isconfigured such that the second step in the communication methodaccording to claim 15 is directed for notifying the control informationon the network to the communication device in the network in associationwith a period in which the communication device in the network performsa communication operation in the first intermittent operation mode or inthe second intermittent operation mode.

An invention according to claim 17 of the present application is acommunication system including a base station for operating acommunication network, and a terminal which includes a communicationprocessing unit for performing digital processing and analog processingfor transmitting and receiving data to and from the base station, sets afirst cycle of a first intermittent operation mode and a second cycle ofa second intermittent operation mode based on control informationnotified from the communication network, determines a period of enteringthe second intermittent operation mode based on the first cycle, turnsoff at least part of circuits in the communication processing unit inother than the period of entering the second intermittent operation modein the first intermittent operation mode, and performs an intermittentoperation on the communication processing unit per second cycle in thesecond intermittent operation mode.

The “system” described herein refers to a logical collection of devices(or function modules for realizing specific functions), and each deviceor function module may be or may not be in a single casing.

According to the present invention, there can be provided, in thecommunication system having a base station accommodating a terminal, acommunication device excellent and capable of intermittently operatingas a terminal suitably while receiving paging information or othernecessary information from the base station, and a communication methodas well as a communication system.

According to the present invention, there can be provided acommunication device excellent and capable of suitably makingcommunication as a terminal while intermittently operating according toa communication schedule desired by users inside and outside thecommunication network, and a communication method as well as acommunication system.

With the invention according to claims 1 to 9 and 13 to 17 of thepresent application, the communication device uses the cycles of DRXwith different lengths in a hierarchy manner thereby to acquirenecessary information from the communication network in short cycle DRXwhile achieving a reduction in consumed power at the terminal in longcycle DRX (long sleep state).

With the invention according to claims 10 and 11 of the presentapplication, since the correction processing such as synchronization orpull-in is performed on the communication processing unit when thecommunication processing unit transits to the ON state and receivesradio frames again, the reception operation can be correctly performedeven in the OFF (sleep) state for a long time.

With the invention according to claim 12 of the present application, twocycles with different lengths in the same DRX mode are defined and thelong cycle is typically used, but when an event occurs, the cycle isswitched to the short cycle, and thus the terminal can rapidly connectto the communication network when an event occurs. Thereby, thecommunication schedule of the terminal can be notified to thecommunication network via the server from the users inside and outsidethe communication network, and the schedule can be reflected ongeneration of the DRX cycle.

Other additional objects, characteristics and advantages of the presentinvention will be apparent with more detailed description based on theembodiment of the present invention and the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram schematically illustrating a structure of acommunication network to which the present invention is applied.

FIG. 2 is a diagram schematically illustrating other structure of thecommunication network to which the present invention is applied.

FIG. 3 is a diagram illustrating an exemplary structure of a radio frametransmitted from a base station to a terminal, which is defined by LTEof 3GPP.

FIG. 4 is a diagram schematically illustrating how resource blocks areallocated.

FIG. 5 is a diagram schematically illustrating an exemplary structure ofa communication device operating as a terminal in a communicationnetwork of a base station.

FIG. 6 is a diagram illustrating an exemplary internal structure of aDRX control unit 56.

FIG. 7 is a diagram illustrating exemplary DRX in which DRX1 having along cycle T_DRX1 and DRX2 having a short cycle T_DRX2 are used in ahierarchy manner.

FIG. 8 is a diagram illustrating another exemplary DRX in which DRX1having a long cycle T_DRX1 and DRX2 having a short cycle T_DRX2 are usedin a hierarchy manner.

FIG. 9 is a diagram illustrating still another exemplary DRX in whichDRX1 having a long cycle T_DRX1 and DRX2 having a short cycle T_DRX2 areused in a hierarchy manner.

FIG. 10 is a flowchart illustrating a processing procedure performed bya communication device 50 operating as a terminal in a communicationnetwork in an intermittent operation (DRX) mode.

FIG. 11 is a flowchart illustrating another exemplary processingprocedure performed by the communication device 50 operating as aterminal in a communication network in the intermittent operation (DRX)mode.

FIG. 12 is a diagram illustrating an exemplary communication sequenceperformed between a communication network and a terminal.

FIG. 13 is a flowchart illustrating a processing procedure performed bythe communication device 50 operating as a terminal corresponding to anoccurred event in a communication network in the intermittent operation(DRX) mode.

FIG. 14 is a flowchart illustrating another exemplary processingprocedure performed by the communication device 50 operating as aterminal corresponding to an occurred event in a communication networkin the intermittent operation (DRX) mode.

FIG. 15 is a diagram illustrating an exemplary communication controlprocedure between a MTC user, a MTC server, a communication network anda MTC terminal.

MODE FOR CARRYING OUT THE INVENTION

An embodiment according to the present invention will be described belowin detail with reference to the drawings.

A structure of a network to which the present invention is applied willbe described first. In the following description, MTC-related parts willbe mainly described but terminals and servers other than MTC may bepresent in a communication network.

FIG. 1 schematically illustrates a structure of a communication networkto which the present invention is applied. In the Figure, thecommunication network is a third generation mobile communication systemwhose specification is defined by 3GPP, for example. The communicationnetwork is configured of at least a base station, and may be arrangedwith a mobility management entity (MME) of a terminal and a gateway (GW)for an external network. The external network described herein is an IP(Internet Protocol) network, for example.

The terminals accommodated in the communication network include MTCterminals not directly used by persons for communication such as meters,automatic vendors and electronic advertisements. The MTC terminal is aterminal for making communication with a MTC user via a communicationnetwork, a MTC server or the like. The MTC user is a user utilizing MTC.For example, person-operating client machines or programs takingpersons' works may be considered as part of the MTC users.

The MTC server is a server present between the MTC user and the MTCterminal, and is directed for converting an application level requestfrom the MTC user into information for the MTC terminal or transmittingthe information for the MTC terminal to the MTC terminal via thecommunication network. The server is not particularly limited in aphysical meaning, and the functions of the MTC server can be provided invarious forms.

In the exemplary structure of the communication network illustrated inFIG. 1, a terminal, a base station, a MME and a GW are arranged,respectively, but multiple ones may be arranged, respectively. In theFigure, the MTC server is present outside the GW or on an externalnetwork. When a MTC user is not an operator of the communicationnetwork, the illustrated structure may be assumed. The MTC user otherthan the operator of the communication network assumes an operator whocollects information from the MTC terminal or distributes information tothe MTC terminal, for example.

FIG. 2 schematically illustrates other structure of the communicationnetwork to which the present invention is applied. It is mainlydifferent from the exemplary structure of the communication networkillustrated in FIG. 1 in that the MTC server is arranged inside thecommunication network.

The MTC server is depicted as a physically-independent device in boththe exemplary structures of the communication network illustrated inFIG. 1 and FIG. 2, but the present invention is not limited thereto, andthe GW or other device may support the functions of the MTC server, forexample.

DRX set in the communication network according to the embodiment of thepresent invention will be next described.

For example, the MTC terminal is relatively lower in a necessarycommunication frequency than normal terminals, and needs to reduceconsumed power of the terminal by DRX. For 3GPP, an outline ofintermittent reception is described as DRX (described above). FIG. 3illustrates an exemplary structure of a radio frame transmitted from thebase station to the terminal, which is defined by LTE of 3GPP. The radioframe is formed in a three-layer hierarchy of time slot (Slot), subframe(Subframe) and radio frame (Radio Frame) in ascending order of timeunit.

A time slot with 0.5 milliseconds is configured of seven OFDM symbols #0to #6 (in the case of unicast transmission), and is a unit of ademodulation processing when being received on the user (mobile station)side. A subframe with one millisecond is configured of two successivetime slots, and is a transmission time unit of a correction-encoded datapacket. A radio frame with 10 milliseconds is configured of tensuccessive subframes #0 to #9 (that is, 20 time slots), and is a basicunit for multiplexing of all the physical channels.

With different subcarriers or different time slots, each terminalaccommodated in the base station may make communication without mutualinterference. A minimum unit of radio resource allocation, which isdirected for blocking successive subcarriers and is called “resourceblock (RB)”, is defined in LTE.

A scheduler mounted on the base station allocates radio resources inunits of resource block to each user. FIG. 4 schematically illustrateshow the resource blocks are allocated. The resource block is configuredof 12 subcarriers×one time slot (7 OFDM symbols=0.5 milliseconds), andin the Figure, the bold-line frame corresponds to one resource block. Upto three OFDM symbols from the head of the subframe are used for acontrol channel called “L1/L2 control signaling” (in the illustratedexample, only one symbol from the head is used for the control channel).The scheduler of the base station can allocate the resource blocks persubframe or at intervals of 1 millisecond. Position information of theresource block is called scheduling. The scheduling information onuplink from the terminal to the base station and the schedulinginformation on downlink from the base station to the terminal are bothdescribed in the downlink control channel. Each user can recognize theresource blocks allocated to him/her through the control channel.

Though omitted in FIG. 3 and FIG. 4, it is noted that channels andsignals are present.

In a radio frame, subframes, slots or symbols storing controlinformation therein are transmitted from the base station at apredetermined time and frequency. The control information describedherein is paging information describing call information or schedulinginformation describing channel allocation, for example. Each terminalaccommodated in the base station receives and acquires the controlinformation thereby to know network information of the network to whichthe terminal is connected, or resource allocation of subframes, slotsand frequencies.

In DRX, the terminal enters the ON state in a predetermined cycle toreceive predetermined subframes, slots or symbols of radio frames amongthe radio frames transmitted from the base station, and enters the OFF(sleep) state in other times. At least the receiver is stopped in theOFF state so that the terminal can achieve a reduction in consumedpower.

FIG. 5 schematically illustrates an exemplary structure of thecommunication device operating as a terminal in the network of the basestation.

The illustrated communication device 50 includes one or more antennas51, an analog processing unit 52, a digital transmission processing unit53, a digital reception processing unit 54, an application processingunit 55, and a DRX control unit 56.

The digital transmission processing unit 53 performs digital modulationsuch as OFDM on transmission data requested to transmit by theapplication processing unit 55. A transmission circuit in the analogprocessing unit 52 analog-converts a digital transmission signal,further up-converts it to a radio frequency band and amplifies its powerto be delivered from the antenna 51.

A reception signal at the antenna 51 is amplified with low noise anddown-converted in a reception circuit in the analog processing unit 52,and then digital-converted. The digital reception processing unit 54performs digital demodulation such as OFDM on a digital receptionsignal, and recovers and passes reception data to the applicationprocessing unit 55. The digital reception processing unit 54 performs asynchronization (or pull-in) processing, frequency correction, channelestimation and the like.

The communication device 50 includes two or more antennas 51 thereby tomake spatial multiplex communication. One or more antennas 51 may beemployed and the present invention is not limited to a specific numberof antennas.

The communication device 50 has a normal operation mode for alwaysoperating the communication processing units such as the analogprocessing unit 52, the digital transmission processing unit 53 and thedigital reception processing unit 54, and a power-saving mode forturning off at least part of the circuits in the communicationprocessing units thereby to reduce consumed power. An exemplarypower-saving mode is an intermittent operation mode for intermittentlyperforming DRX or a communication operation of the communicationprocessing units, where at least part of the circuits in thecommunication processing units is turned off in a period in which thecommunication operation stops, thereby achieving low consumed power. TheDRX control unit 56 controls for causing the communication processingunits to perform the intermittent communication operation in theintermittent operation mode while the communication device 50 isacquiring necessary information from the communication network.

Generally, the intermittent operation repeatedly switches on and off thecommunication operation of the communication processing units with acycle of DRX. When a rate of the period in which the communicationoperation is turned on in the cyclic period, that is, a duty ratio islow, low consumed power is more effective but a time in whichinformation can be acquired from the communication network is shorter.The most basic intermittent operation employs only one DRX cycle, but tothe contrary, the network according to the present embodiment is mainlycharacterized in that a period for the intermittent operation isdetermined in combination of the cycles of DRX with different lengths ina hierarchy manner. Upper DRX in the hierarchy has a longer cycle thanlower DRX. A period using the cycle of the immediately lower DRX isdetermined based on the information on the cycle of the upper DRX.

In the period using the information on the cycle of the lowermost DRX,the intermittent operation of the communication processing units iscontrolled based on the information on the cycle of the DRX. In thepresent specification, a period using the information on the cycle ofthe lowermost DRX is called “intermittent operation period.” Thecommunication device 50 in the intermittent operation mode performs theintermittent operation on the communication processing units only in theintermittent operation period, and keeps at least part of the circuitsin the communication processing units in the OFF state (the long sleepstate) in the long period other than the intermittent operation period,thereby achieving low consumed power. The communication device 50 in theintermittent operation mode activates the communication operation of thecommunication processing units only in the intermittent operation periodthereby to set the intermittent operation period for acquiring necessaryinformation from the communication network.

The number of cycles or modes of DRX used in a hierarchy manner is notparticularly limited. In the following, for simplified description,assuming that two cycles of DRX with different lengths of the first DRX“DRX1” with a long cycle T_DRX1 and the second DRX “DRX2” with a shortcycle T_DRX2 (where, T_DRX1>T_DRX2) and immediately lower than the DRX1are used in a hierarchy manner, the operations of the communicationnetwork will be considered.

The DRX control unit 56 in FIG. 5 uses the information on the cycleT_DRX1 of the upper DRX1 to determine a period using the information onthe cycle T_DRX2 of the lower DRX2. Since the DRX2 is the lowermost DRX,the period using the information on the cycle T_DRX2 corresponds to theintermittent operation period, and in the period, the information on thecycle T_DRX2 is used to control the intermittent operation of thecommunication processing units. Since the communication operation stopsin the long period other than the intermittent operation period in theintermittent operation mode, at least part of the circuits in thecommunication processing units is kept in the OFF state (in the longsleep state), thereby achieving low consumed power. The communicationdevice 50 in the intermittent operation mode activates the communicationoperation of the communication processing units only in the intermittentoperation period, and thus the cycle T_DRX1 of the DRX1 and the cycleT_DRX2 of the DRX2 are set in the communication network for the properintermittent operation period in which necessary information can beacquired from the communication network. In the present specification,information on DRX in the communication network including theinformation on the cycle T_DRX1 of the DRX1 and the information on thecycle T_DRX2 of the DRX2 will be called “DRX control information.”

FIG. 6 illustrates an exemplary internal structure of the DRX controlunit 56. The DRX control unit 56 includes a DRX information setting unit61, a DRX switch unit 62, a DRX1 determination unit 63, a DRX2determination unit 64, and a timing count unit 65.

The DRX information setting unit 61 sets the DRX switch unit 62, theDRX1 determination unit 63 and the DRX2 determination unit 64 accordingto the DRX control information received from the application processingunit 55. The DRX information setting unit 61 uses a timing count signalfrom the timing count unit 65 to generate a DRX1 timing signal with thecycle T_DRX1 of the DRX1 and a DRX2 timing signal with the cycle T_DRX2of the DRX2 and to supply them to the DRX switch unit 62, the DRX1determination unit 63 and the DRX2 determination unit 64. The DRXcontrol information includes information on a duty ratio between thecycle T_DRX1 of the DRX1 and the DRX1 timing signal and a duty ratiobetween the cycle T_DRX2 of the DRX2 and the DRX2 timing signal. Theinformation on the duty ratios described herein may be the values of theduty ratios, or the values directly indicating the length of the ONperiod and the length of the OFF period of the DRX1 timing signal andthe DRX2 timing signal.

The DRX switch unit 62 switches to the period using the DRX2 timingsignal or the intermittent operation period based on the ON/OFF switchtiming of the DRX1 timing signal input from the DRX information settingunit 61, and inputs an instruction into the DRX1 determination unit 63and the DRX2 determination unit 64.

The DRX1 determination unit 63 compares the DRX1 timing signal inputfrom the DRX information setting unit 61 with the timing count signalinput from the timing count unit 65, and controls the intermittentoperation of the digital reception processing unit 54 and the analogprocessing unit 52 in the period other than the intermittent operationperiod in the intermittent operation mode.

The DRX2 determination unit 64 compares the DRX2 timing signal inputfrom the DRX information setting unit 61 with the timing count signalinput from the timing count unit 65, and controls the intermittentoperation of the digital transmission processing unit 53, the digitalreception processing unit 54 and the analog processing unit 52 in theintermittent operation period.

FIG. 7 illustrates exemplary DRX using DRX1 with a long cycle T_DRX1 andDRX2 with a short cycle T_DRX2 in a hierarchy manner (T_DRX1≦T_DRX2). Inthe illustrated example, the intermittent operation period is as long asthe ON period of the upper DRX1 timing signal and the communicationoperation is performed only in the ON period of the lower DRX2 timingsignal in the intermittent operation period. Thus, the ON period of theupper DRX1 timing signal is inevitably longer than the ON period of thelower DRX2 timing signal.

The intermittent operation period in which the communication processingunits are intermittently operated based on the immediately lower DRX2timing signal is set based on the upper DRX1 timing signal in thehierarchy DRX.

In the example illustrated in FIG. 7, when entering the ON period of theDRX1 timing signal, the DRX switch unit 62 determines to start theintermittent operation period, and entering the OFF period of the DRX1timing signal, determines to terminate the intermittent operationperiod. The DRX1 determination unit 63 keeps at least part of thecircuits in the digital transmission processing unit 53, the digitalreception processing unit 54 and the analog processing unit 52 in theOFF state in other than the intermittent operation period (that is, putsthe terminal in the long sleep state).

When entering the intermittent operation period, the DRX2 determinationunit 64 determines ON/OFF of the DRX2 timing signal, and turns on thedigital transmission processing unit 53, the digital receptionprocessing unit 54 and the analog processing unit 52 in the ON period ofthe DRX2 timing signal, and waits for the control information to bereceived from the radio frames or the communication network (the basestation). The DRX2 determination unit 64 turns off the digitaltransmission processing unit 53, the digital reception processing unit54 and the analog processing unit 52 in the OFF period of the DRX2timing signal (that is, puts the terminal in the short sleep state).

The cycles of DRX with different lengths are used in a hierarchy manneras illustrated in FIG. 7 so that the terminal can acquire necessaryinformation from the communication network in the short DRX cycle whileachieving a reduction in consumed power of the terminal in the long DRXcycle. The number of cycles of the hierarchy DRX is not limited to two.The DRX unit is a subframe, but reception is possible in other unit.

FIG. 8 illustrates other exemplary DRX using DRX1 with a long cycleT_DRX1 and DRX2 with a short cycle T_DRX2 in a hierarchy manner.T_DRX1>T_DRX2 is assumed. In the illustrated example, a rise of theupper DRX1 timing signal is used to determine the start point and theend point of the intermittent operation period, and thus the length ofthe ON period is meaningless. Since the communication operation isperformed only in the ON period of the lower DRX2 timing signal in theintermittent operation period, when a duty ratio is made higher, thereception chances increase but lower consumed power is less effective.

The intermittent operation period for intermittently operating thecommunication processing units based on the immediately lower DRX2timing signal is set based on the upper DRX1 timing signal in thehierarchy DRX. While the intermittent operation period is in the ONperiod of the DRX1 timing signal in the example illustrated in FIG. 7,the intermittent operation period starts when the DRX1 timing signal isturned on outside the intermittent operation period and the intermittentoperation period ends when the DRX1 timing signal is turned on in theintermittent operation period in the example illustrated in FIG. 8 (thatis, whenever the DRX1 timing signal is turned on, the intermittentoperation period alternately starts and ends in a repeated manner).

In the example illustrated in FIG. 8, the DRX switch unit 62 determinesto start the intermittent operation period when the DRX1 timing signalis turned on not in the DRX2 mode. The DRX switch unit 62 determines toterminate the intermittent operation period when the DRX1 timing signalis turned on in the intermittent operation period.

The DRX2 determination unit 64 determines ON/OFF of the DRX2 timingsignal in the intermittent operation period, and turns on the digitaltransmission processing unit 53, the digital reception processing unit54 and the analog processing unit 52 and waits for the controlinformation to be received from the communication network (the basestation) in the ON period of the DRX2 timing signal. The DRX2determination unit 64 turns off the digital transmission processing unit53, the digital reception processing unit 54 and the analog processingunit 52 in the OFF period of the DRX2 timing signal (that is, puts theterminal in the short sleep state). The DRX1 determination unit 63 turnsoff the digital transmission processing unit 53, the digital receptionprocessing unit 54 and the analog processing unit 52 in the period otherthan the intermittent operation period (that is, puts the terminal inthe long sleep state).

The cycles of DRX with different lengths are used in a hierarchy manneras illustrated in FIG. 8 so that the terminal can acquire necessaryinformation from the communication network in the short DRX cycle whileachieving a reduction in consumed power of the terminal in the long DRXcycle. The number of cycles of the hierarchy DRX is not limited to two.The DRX unit is a subframe, but reception is possible in other unit.

FIG. 9 illustrates still another exemplary DRX using the DRX1 mode witha long cycle T_DRX1 and the DRX2 mode with a short cycle T_DRX2 in ahierarchy manner. T_DRX1>T_DRX2 is assumed. In the illustrated example,it may be desirable that the ON period of the upper DRX1 timing signalis longer than the ON period of the lower DRX2 timing signal (ditto).Since the intermittent operation period is as long as the ON period ofthe upper DRX1 timing signal, when the duty ratio is made higher, thereception chances increase. Since a rise of the lower DRX2 timing signalis used to determine the start point and the end point of thecommunication operation in the intermittent operation period, the lengthof the ON period is meaningless.

The intermittent operation period for intermittently operating thecommunication processing units based on the immediately lower DRX2timing signal is set based on the upper DRX1 timing in the hierarchyDRX. In the example illustrated in FIG. 9, the intermittent operationperiod is in the ON period of the DRX1 timing signal similarly as in theexample illustrated in FIG. 7. While the communication operation isperformed in the ON period of the DRX2 timing signal in the intermittentoperation period in the example illustrated in FIG. 7, the communicationoperation starts when the DRX2 timing signal is turned on while thecommunication operation is stopping in the intermittent operationperiod, and the communication operation stops when the DRX2 timingsignal is turned on during the communication operation (that is,whenever the DRX2 timing signal is turned on, the communicationoperation alternately starts and stops in a repeated manner) in theexample illustrated in FIG. 9.

In the example illustrated in FIG. 9, the DRX switch unit 62 determinesto start the intermittent operation period when entering the ON periodof the DRX1 timing signal, and determines to terminate the intermittentoperation period when entering the OFF period of the DRX1 timing signal.The DRX1 determination unit 63 keeps at least part of the circuits inthe digital transmission processing unit 53, the digital receptionprocessing unit 54 and the analog processing unit 52 in the OFF state inother than the intermittent operation period (that is, puts the terminalin the long sleep state).

In the intermittent operation period, the DRX2 determination unit 64starts the communication operation when the DRX2 timing signal is turnedon while the communication processing units such as the digitaltransmission processing unit 53, the digital reception processing unit54 and the analog processing unit 52 stop the communication operation,and waits for the control information to be received from the radioframes or the communication network (the base station). When the DRX2timing signal is turned on during the communication operation of thecommunication processing units, the communication operation of thecommunication processing units stops (that is, the terminal is put inthe sleep state). Thereafter, whenever the DRX2 timing signal is turnedon, the reception waiting state and the (short) sleep state arealternately switched.

The cycles of DRX with different lengths are used in a hierarchy manneras illustrated in FIG. 9, the terminal can acquire necessary informationfrom the communication network in the short DRX cycle while achieving areduction in consumed power of the terminal in the long DRX cycle. Thenumber of cycles of the hierarchy DRX is not limited to two. The DRXunit is a subframe, but reception is possible in other unit.

In the examples illustrated in FIG. 7 to FIG. 9, the radio frame arecontinuously received only in the intermittent operation period in theintermittent operation mode. However, when the terminal can finish allthe required reception processing in the intermittent operation period,the communication processing units may exit the intermittent operationperiod and may be turned off without waiting for the intermittentoperation period determined based on the DRX1 timing signal to end.Thereby, the terminal can further achieve a reduction in consumed power.

When the cycles of DRX with different lengths are used in a hierarchymanner as described above, it is assumed that the MTC terminal in theintermittent operation mode is in the OFF (sleep) state for a long timeother than the intermittent operation period. Thus, when the MTCterminal transits to the ON state and receives the radio frames again,correction (synchronization or pull-in) of the receiver may be required.A method using a known part of a signal transmitted from the basestation, or the like is specifically assumed in order to correct thereceiver, but the present invention is not limited to a specificcorrection method.

For a timing when the MTC terminal corrects the receiver, it is assumedthat pull-in or synchronization is performed when the receiver is not inON after the intermittent operation period starts. Thereby, it ispossible to correct the receiver in order to keep the reception qualitywhile achieving a reduction in consumed power when the communicationprocessing units are in the OFF (sleep) state in the period other thanthe intermittent operation period determined by the DRX1 timing signal.The receiver may be corrected in other timing. For example, also in theOFF state other than the intermittent operation period, the terminal mayvoluntarily make a correction. In this case, the terminal temporarilyenters the ON state.

FIG. 10 illustrates the processing procedure performed by thecommunication device 50 operating as a terminal in the communicationnetwork in the intermittent operation (DRX) mode in a form of flowchart.Herein, when entering the intermittent operation mode, the terminal usesthe long cycle T_DRX1 and the short cycle T_DRX2 in a hierarchy manner.

When the intermittent operation mode starts according to thedetermination by the DRX switch unit 62 (step S1001), the digitalreception processing unit 54 performs a correction processing such assynchronization or pull-in before the communication processing units areturned on (step S1002).

Thereafter, the DRX switch unit 62 monitors the DRX1 timing signal andwaits for a timing of entering the intermittent operation period toarrive (No in step S1003). Then, when the timing of entering theintermittent operation period arrives (Yes in step S1003), the terminalenters the intermittent operation period (step S1004).

In the intermittent operation period, the DRX2 determination unit 64compares the DRX2 timing signal input from the DRX information settingunit 61 with the timing count signal input from the timing count unit65, and waits for a period for performing the reception operation toarrive (No in step S1005).

Then, when the period for performing the reception operation arrives(Yes in step S1005), the DRX2 determination unit 64 turns on thereceiver, that is, the digital reception processing unit 54 and theanalog processing unit 52, and receives predetermined controlinformation from the communication network (step S1006).

The control information described herein is paging informationdescribing call information or scheduling information describing channelallocation, for example. The control information received from thecommunication network is analyzed to check whether a channel isallocated to the terminal (step S1007). When a channel is allocated (Yesin step S1007), the digital reception processing unit 54 and the analogprocessing unit 52 receive the allocated channel (step S1008), andperforms processing according to the contents received in theapplication processing unit 55 (step S1009).

Thereafter, the DRX switch unit 62 checks whether to continue theintermittent operation period based on the DRX1 timing signal (stepS1010). When the DRX2 mode is to be continued (Yes in step S1010), theprocessing returns to step S1005 to wait for the period for performingthe reception operation to arrive. When the intermittent operationperiod is not to be continued (No in step S1010), the processing returnsto step S1001.

FIG. 11 illustrates another exemplary processing procedure performed bythe communication device 50 operating as a terminal in the communicationnetwork in the intermittent operation (DRX) mode in a form of flowchart.Herein, when entering the intermittent operation mode, the terminal usesthe long cycle T_DRX1 and the short cycle T_DRX2 in a hierarchy manner(ditto).

When the intermittent operation mode starts according to thedetermination by the DRX switch unit 62 (step S1101), the DRX switchunit 62 monitors the DRX1 timing signal, and waits for a timing ofentering the intermittent operation period to arrive (No in step S1102).Then, when the timing of entering the intermittent operation periodarrives (Yes in step S1102), the terminal enters the intermittentoperation period (step S1103).

When entering the intermittent operation period, the receiver or thedigital reception processing unit 54 performs the correction processingsuch as synchronization or pull-in before the receiver is turned on(step S1104).

In the intermittent operation period, the DRX2 determination unit 64compares the DRX2 timing signal input from the DRX information settingunit 61 with the timing count signal input from the timing count unit65, and waits for a period for performing the reception operation toarrive (No in step S1105).

When the period for performing the reception operation arrives (Yes instep S1105), the DRX2 determination unit 64 turns on the receiver, thatis, the digital reception processing unit 54 and the analog processingunit 52, and receives predetermined control information from thecommunication network (step S1106).

Then, the control information received from the communication network isanalyzed and a check is made as to whether a channel is allocated to theterminal (step S1107). Then, when a channel is allocated (Yes in stepS1107), the digital reception processing unit 54 and the analogprocessing unit 52 receive the allocated channel (step S1108), andperform processing according to the contents received in the applicationprocessing unit 55 (step S1109).

Thereafter, the DRX switch unit 62 checks whether to continue theintermittent operation period based on the DRX1 timing signal (stepS1110). When the intermittent operation period is to be continued (Yesin step S1110), the processing returns to step S1105 to wait for theperiod for performing the reception operation to arrive. When theintermittent operation period is not to be continued (No in step S1110),the processing returns to step S1001.

FIG. 12 illustrates an exemplary communication sequence performedbetween the communication network and the MTC terminal.

In the communication network, for example, the base station generatesDRX control information necessary for performing DRX at the terminal(SEQ1201). Herein, the DRX control information is generated for using aplurality of DRX modes with different cycles in a hierarchy manner. TheDRX control information includes the information on the cycle T_DRX1 ofthe DRX1 and the information on the cycle T_DRX2 of the DRX2. Then, thegenerated DRX control information is notified to the MTC terminal fromthe communication network (SEQ1202).

Then, the MTC terminal sets the cycles and the duty ratios of the DRX1timing signal and the DRX2 timing signal based on the received DRXcontrol information, and performs DRX according to any operationprocedure illustrated in FIG. 7 to FIG. 9, for example (SEQ1203).

The communication network generates system information, paginginformation, scheduling information and the like (SEQ1204). Then, afterthe cycles and the duty ratios of the DRX1 timing signal and the DRX2timing signal are set for the MTC terminal as described above, thesystem information, the paging information, the scheduling informationand the like are transmitted to the MTC terminal so as to conform to thecycles (or the subframes in which the MTC terminal performs thereception operation) (SEQ1205).

When receiving the system information, the paging information, thescheduling information and the like, the MTC terminal performsprocessing according to the information (SEQ1206). Thereby, the MTCterminal can both reduce consumed power with the long cycle T_DRX1 (thelong sleep state) and acquire necessary information from thecommunication network.

In the exemplary communication sequence illustrated in FIG. 12, it isassumed that DRX in the MTC terminal is basically set from thecommunication network side. Typically, DRX is set from the communicationnetwork side according to a communication frequency of the networkinformation.

However, it is assumed that the MTC terminal is in the sleep state for along time, but communication may be needed due to an occurrence of anevent at a timing other than the initial schedule. The event describedherein may include an emergency situation or failure occurring in theMTC terminal. In consideration of convenience of the MTC, even when suchan event occurs, the communication network and the MTC terminal need toproperly operate. In the following, the DRX control system depending onan occurred event will be considered.

There has been employed, as an example in which the cycles of DRX withdifferent lengths are used in a hierarchy manner, the case in which twoDRX modes of the first DRX “DRX1” with a long cycle T_DRX1 and thesecond DRX “DRX2” with a short cycle T_DRX2 (where T_DRX1>T_DRX2) andimmediately lower than the DRX1 are used in a hierarchy manner. To thecontrary, two cycles with different lengths of T_DRX1 a and T_DRX1 b aredefined as the cycles corresponding to the DRX1 (where T_DRX1 a>T_DRX1b) in case the communication is needed due to an occurred event. TheDRX1 timing signal driven at the cycle T_DRX1 a is typically used todetermine the intermittent operation period, but when an event occurs,the cycle is switched to the DRX1 timing signal driven at T_DRX1 b todetermine the intermittent operation period. Specifically, the DRXinformation setting unit 61 may change the DRX1 cycle from T_DRX1 a toT_DRX1 b to change the DRX1 timing signal, and the DRX switch unit 62may determine the intermittent operation period by use of the changedDRX1 timing signal. With the cycle switching, the terminal can rapidlymake connection to the communication network when an event occurs.

FIG. 13 illustrates a processing procedure performed by thecommunication device 50 operating as a terminal corresponding to anoccurred event in the communication network in the intermittentoperation (DRX) mode in a form of flowchart.

When the intermittent operation mode starts according to thedetermination by the DRX switch unit 62 (step S1301), the DRXinformation setting unit 61 first sets the cycle of the DRX1 at T_DRX1 aand then generates the DRX1 timing signal.

Then, a check is made as to whether a predetermined event has occurredin the intermittent operation mode (in the period not in theintermittent operation period) (step S1302).

For an event, an occurrence of an even at the application layer level inthe MTC terminal or sensor detection is assumed. The present inventionis not limited to a specific event detection method.

When a predetermined event has occurred (Yes in step S1302), the DRXinformation setting unit 61 switches the cycle of the DRX1 from T_DRX1 ato T_DRX1 b thereby to change the DRX1 timing signal (step S1303).Consequently, the DRX switch unit uses the changed DRX1 timing signal todetermine the intermittent operation period.

On the other hand, when a predetermined event has not occurred (No instep S1302), the DRX information setting unit 61 generates the DRX1timing signal with the cycle of the DRX1 kept at T_DRX1 a, and the DRXswitch unit 62 uses the DRX1 timing signal to determine the intermittentoperation period.

The DRX switch unit 62 monitors the DRX1 timing signal and waits for atiming of entering the intermittent operation period to arrive (No instep S1304). Then, when the timing of entering the intermittentoperation period arrives (Yes in step S1304), the terminal enters theintermittent operation period (step S1305).

When entering the intermittent operation period, the receiver or thedigital reception processing unit 54 performs the correction processingsuch as synchronization or pull-in prior to activating the receptionoperation (step S1306).

In the intermittent operation period, the DRX2 determination unit 64compares the DRX2 timing signal input from the DRX information settingunit 61 with the timing count signal input from the timing count unit65, and waits for a period for performing the reception operation toarrive (No in step S1307).

Then, when the period for performing the reception operation arrives(Yes in step S1307), the DRX2 determination unit 64 turns on thereceiver, that is, the digital reception processing unit 54 and theanalog processing unit 52, and receives predetermined controlinformation from the communication network (step S1308).

Then, the control information received from the communication network isanalyzed and a check is made as to whether a channel is allocated to theterminal (step S1309). Then, when a channel is allocated (Yes in stepS1309), the digital reception processing unit 54 and the analogprocessing unit 52 receive the allocated channel (step S1310), andperforms processing according to the contents received in theapplication processing unit 55 (step S1311).

Thereafter, the DRX switch unit 62 checks whether to continue theintermittent operation period based on the DRX1 timing signal (stepS1312). When the intermittent operation period is to be continued (Yesin step S1312), the processing returns to step S1307 to wait for aperiod for performing the reception operation to arrive. When theintermittent operation is not to be continued (No in step S1312), theprocessing returns to step S1301.

FIG. 14 illustrates another exemplary processing procedure performed bythe communication device 50 operating as a terminal corresponding to anoccurred event in the communication network in the intermittentoperation (DRX) mode in a form of flowchart.

When the intermittent operation mode starts according to thedetermination by the DRX switch unit 62 (step S1401), the DRXinformation setting unit 61 sets the cycle of the DRX1 at T_DRX1 a andgenerates the DRX1 timing signal.

Then, a check is made as to whether a predetermined event has occurredin the intermittent operation mode (in the period not in theintermittent operation period) (step S1402).

Herein, when a predetermined event has occurred (Yes in step S1402), theterminal exits the intermittent operation mode and enters the normalcommunication state to always perform the reception operation (stepS1403). Then, the terminal issues a request of connecting to thecommunication network (the base station) (step S1404), and whenconnection is established, performs the communication processingaccording to the predetermined contents (step S1405). Thereafter, theterminal returns to step S1401.

On the other hand, when a predetermined event has not occurred (No instep S1402), the DRX switch unit 62 monitors the DRX1 timing signal andwaits for a timing of entering the intermittent operation period toarrive (No in step S1406). Then, when the timing of entering theintermittent operation period arrives (Yes in step S1406), the terminalenters the intermittent operation period (step S1407).

When entering the intermittent operation period, the receiver or thedigital reception processing unit 54 performs the correction processingsuch as synchronization or pull-in before the receiver is turned on(step S1408).

In the intermittent operation period, the DRX2 determination unit 64compares the DRX2 timing signal input from the DRX information settingunit 61 with the timing count signal input from the timing count unit65, and waits for a period for performing the reception operation toarrive (No in step S1409).

When the period for performing the reception operation arrives (Yes instep S1409), the DRX2 determination unit 64 turns on the receiver, thatis, the digital reception processing unit 54 and the analog processingunit 52, and receives predetermined control information from thecommunication network (step S1410).

Then, the control information received from the communication network isanalyzed, and a check is made as to whether a channel is allocated tothe terminal (step S1411). Then, when a channel is allocated (Yes instep S1411), the digital reception processing unit 54 and the analogprocessing unit 52 receive the allocated channel (step S1412) andperform processing according to the contents received in the applicationprocessing unit 55 (step S1413).

Thereafter, the DRX switch unit 62 checks whether to continue theintermittent operation period based on the DRX1 timing signal (stepS1414). When the intermittent operation period is to be continued (Yesin step S1414), the processing returns to step S1409 to wait for aperiod for performing the reception operation to arrive. When theintermittent operation period is not to be continued (No in step S1414),the processing returns to step S1401.

MTC applications may include meters, automatic vendors, electronicadvertisements and the like. Thus, an intention of the MTC user isdesirably reflected on the communication contents and the communicationschedule of the MTC terminal. Particularly, the communication schedulelargely has a relationship with DRX. In consideration of the MTCapplications, it is naturally expected that the communication scheduleis longer, such as daily, weekly and monthly, unlike the typicalcommunication.

The communication schedule desired by the MTC user needs to be put underthe DRX control on the communication network side in order toefficiently apply the DRX control to the system. Therefore, it isdesirable that a function of notifying the communication scheduledesired by the MTC user to the communication network is inside thecommunication network or outside the communication network. A MTC serveris assumed for realizing the function.

FIG. 15 illustrates an exemplary communication control procedure betweenthe MTC user, the MTC server, the communication network and the MTCterminal. In the Figure, the MTC user, the MTC server, the communicationnetwork and the MTC terminal are classified not physically butlogically. For example, the MTC server can also have the functions ofthe MTC user or the GW in the communication network can also have thefunctions of the MTC server. In FIG. 15, only exchange of information atthe logic level and in the application layer is noted, and ACK/NACK orretransmission when a communication error occurs in the lower layer isomitted. Any protocol is applicable to the protocol in the lower layer.

The functions of the MTC server for controlling DRX with respect to thecommunication network may have the following.

(1) A function of receiving information on the contents of the MTC orthe schedule from the MTC user.

(2) A function of notifying the communication interval and the cycle ofthe target MTC terminal to the communication network based on theschedule.

For the function (1), the information input from the MTC user may bemanually input by the MTC user or may be automatically generated by theMTC user (the client machine). The input method is not limited.

For the function (2), the MTC server may simply notify the scheduleinformation as time information to the communication network or mayconvert and notify it into a unit (radio frame, subframe, slot or thelike) according to the frame structure of the communication network tothe communication network.

When receiving the schedule information from the MTC server, thecommunication network generates control information on the actual DRXfrom the schedule, and controls DRX of the target MTC terminal. The DRXcontrol information is notified to the MTC terminal via the basestation. The schedule information received from the MTC server can belonger (time, day, week, month or the like) as time information handledby the communication network. Thus, it is desirable to consider ahierarchy of DRX at the communication network level such that the MTCterminal can both reduce consumed power and acquire the networkinformation. The longest DRX cycle needs to be shorter than the schedulecycle set by the MTC user in the DRX setting at the communicationnetwork level.

INDUSTRIAL APPLICABILITY

The present invention has been described above in detail with referenceto the specific embodiment. However, it is apparent that those skilledin the art can modify or replace the embodiment without departing fromthe spirit of the present invention.

The embodiment in which the present invention is applied to thecommunication network based on the data communication specificationdefined by LTE of 3GPP has been mainly described in the presentspecification, but the present invention is not limited thereto. Thepresent invention is applicable to various types of communicationnetworks configured of the base stations accommodating terminals.

The embodiment in which the present invention is applied to the MTCterminal not directly used by persons for communication has been mainlydescribed in the present specification, but the present invention is notlimited thereto. The present invention is applicable to various types ofterminals directly used by persons for communication other than MTC, orvarious types of communication systems other than illustrated ones inFIG. 1 and FIG. 2.

That is, the present invention is disclosed by way of example, and thedescribed contents in the present specification should not be definitelyinterpreted. The range of claims should be considered for determiningthe spirit of the present invention.

REFERENCE SIGNS LIST

-   50 Communication device-   51 Antenna-   52 Analog processing unit-   53 Digital transmission processing unit-   54 Digital reception processing unit-   55 Application processing unit-   56 DRX control unit-   61 DRX information setting unit-   62 DRX switch unit-   63 DRX1 determination unit-   64 DRX2 determination unit-   65 Timing count unit

The invention claimed is:
 1. A communication device, comprising:communication processing circuitry configured to receive data; and atleast one processor configured to: determine whether to enter anintermittent operation period for an intermittent operation of thecommunication processing circuitry per second cycle based on informationon a first cycle longer than the second cycle, and intermittentlyoperate the communication processing circuitry; generate a first timewhich is switched on or off by the first cycle and a second time whichis switched on or off by the second cycle based on control informationon the first cycle and the second cycle from a base station; anddetermine the intermittent operation period based on the first time,wherein the communication processing circuitry is intermittentlyoperated based on the second time in the intermittent operation period.2. The communication device according to claim 1, wherein thecommunication device is configured to operate in a normal operationmode, in which the communication processing circuitry is furtherconfigured to execute a communication operation, and an intermittentoperation mode in which the communication processing circuitry isfurther configured to intermittently execute the communicationoperation, and the at least one processor is further configured todetermine, based on the first cycle, whether to enter the intermittentoperation period in the intermittent operation mode.
 3. Thecommunication device according to claim 1, wherein the at least oneprocessor is further configured to turn off at least one circuit of thecommunication processing circuitry in a period other than theintermittent operation period.
 4. The communication device according toclaim 1, wherein a first ON period of the first time is longer than asecond ON period of the second time.
 5. The communication deviceaccording to claim 1, wherein, based on a first ON period of the firsttime that corresponds to the intermittent operation period, the at leastone processor is further configured to: turn off at least one circuit ofthe communication processing circuitry in a first OFF period of thefirst time, turn on a communication operation of the communicationprocessing circuitry in a second ON period of the second time in theintermittent operation period, and turn off the communication processingcircuitry in a second OFF period of the second time in the intermittentoperation period.
 6. The communication device according to claim 1,wherein the at least one processor is further configured to: start theintermittent operation period based on the first time that is turned onin a period other than the intermittent operation period, terminate theintermittent operation period based on the first time that is turned onin the intermittent operation period, turn on a communication operationof the communication processing circuitry in a second ON period of thesecond time in the intermittent operation period, and turn off at leastone circuit of the communication processing circuitry in a second OFFperiod of the second time.
 7. The communication device according toclaim 1, wherein, based on a first ON period of the first time thatcorresponds to the intermittent operation period, the at least oneprocessor are configured to: turn off at least one circuit of thecommunication processing circuitry in a first OFF period of the firsttime, turn on a communication operation of the communication processingcircuitry, based on the second time that is turned on in an OFF state ofthe communication processing circuitry in the intermittent operationperiod, and turn off the communication processing circuitry, based onthe second time that is turned on in an ON state of the communicationoperation of the communication processing circuitry.
 8. Thecommunication device according to claim 1, wherein, based on an end ofthe reception from a communication network, the at least one processoris further configured to turn off at least one circuit of thecommunication processing circuitry in a period, wherein the period isdetermined to turn on the communication processing circuitry based onthe second time in the intermittent operation period.
 9. Thecommunication device according to claim 1, wherein a correction processis executed on a receiver in the communication processing circuitrybased on at least one or more circuit of the communication processingcircuitry that enters the intermittent operation period from an OFFstate and receives radio frames from a communication network.
 10. Thecommunication device according to claim 9, wherein a correction processis executed on the receiver in the communication processing circuitry inthe intermittent operation period and in the OFF state of thecommunication processing circuitry.
 11. The communication deviceaccording to claim 1, further comprising a first-2 cycle shorter thanthe first cycle, wherein the at least one processor is furtherconfigured to determine, in an occurrence of an event, whether to enterthe intermittent operation period based on the first-2 cycle when apredetermined event occurs.
 12. A communication method comprising:determining whether to enter an intermittent operation period forintermittently operating a communication device based on information ona first cycle; generating a first time which is switched on or off bythe first cycle and a second time which is switched on or off by asecond cycle based on control information on the first cycle and thesecond cycle from a base station; and determining the intermittentoperation period based on the first time and intermittently operatingthe communication device based on the second time in the intermittentoperation period.
 13. The communication method according to claim 12,wherein the communication device is operates in a normal operation mode,in which the communication device executes a communication operation,and an intermittent operation mode in which the communication deviceintermittently executes the communication operation, and wherein thecommunication device is turned off in a period other than theintermittent operation period in the intermittent operation mode.
 14. Acommunication method, comprising: receiving, by a communication devicein a communication network, first parameters of a first cycle and secondparameters of a second cycle shorter than the first cycle; receiving, bythe communication device, control information on the communicationnetwork in association with a period, wherein the period is determinedbased on the first cycle or the second cycle; generating a first timewhich is switched on or off by the first cycle and a second time whichis switched on or off by the second cycle based on the received controlinformation from a base station; and determining an intermittentoperation period based on the first time and intermittently operatingthe communication device based on the second time in the intermittentoperation period.
 15. The communication method according to claim 14,wherein the received control information on the communication network isin association with the period in which a communication operation isturned on based on the second cycle in the intermittent operationperiod, wherein the second cycle is determined by the communicationdevice based on the first cycle.
 16. A communication system comprising:a base station that operates in a communication network; and a terminalcomprising; communication processing circuitry configured to receivedata from the base station; and at least one processor configured to:set a first cycle and a second cycle based on first parameters of thefirst cycle and second parameters of the second cycle shorter than thefirst cycle, wherein the first parameters are received by the terminalfrom the communication network; determine a period to enter anintermittent operation mode based on the first cycle; determine whetherto enter an intermittent operation period for an intermittent operationof the communication processing circuitry per the second cycle based onthe first cycle, and intermittently operate the communication processingcircuitry; generate a first time which is switched on or off by thefirst cycle and a second time which is switched on or off by the secondcycle based on control information on the first and second cycles fromthe base station; and determine the intermittent operation period basedon the first time wherein the communication processing circuitry isintermittently operated based on the second time in the intermittentoperation period.